I have a driving school coming up. Its an Evolution autocross driving school. It is made up of 24 instructed runs. I bought new Dunlop ZII tires on Enkei RPF1 wheels and will be running those for all my autocross events this year. Being that the school is in Late march and its possible to have temperatures in the 40's and 50's will the ZII tires be okay in those temperatures?

I would assume they will need a couple runs to warm up but after that they should be fine right?

 

My experience with the Dunlop ZI's is that they will do fine at those temps once you get them warmed up.

 

Direzza ZII tires are not intended to be driven through snow, on ice or in near-freezing temperatures. So once warmed up they should be fine.

 

I hope you have them heat cycled before the event. The last thing you want is to not create the proper chemical bond/reaction with the rubber before you thrash them through your fun

 

Heat cycling is for R compound tires and not for street tires.

Dunlop Direzza ZII is a DOT street tire and you will be fine.

It's OK to take the first few times out a little more cautiously for EVO school, which phase are you doing?

Do drive around on the ZII to break them in a little.

 

Phase 1, it's my second year of autocross so I am looking forward to more seat time and the instruction. I will put them on a week or so before the event.

Thanks!

 

Phase one is excellent for both novice and experienced autocrosser.

I've taken it twice one year apart and did much better the second time.

Your tires will be fine just try to set the pressures as best you can and leave them, you could possibly run them in your first session out then check the tire tread temperatures as soon as you finish your runs to see where you are at.

Usually it will be three runs in the morning for the instructors to see how you are already doing, check the temperatures and adjust your pressures accordingly then leave them there for the rest of the day. It will be colder in the morning and the temperatures will be lower, pressures will change less. If it warms up by more than 15 degrees then reset pressures a little for the afternoon, you may find that pressures are up by lunchtime vs the morning. Anything more than about 5psi you can reset. Also see how the car is handling, if it feels OK then leave it alone and focus on your driving.

Just as an exercise you can practice the following on the street as you drive:

Look ahead, far far ahead. Move your head right and left and look out the side windows as you scan. (like you are checking traffic before you cross a busy road)

And be sure to get enough rest the night or two before the class.

 

Should I bring an air tank? I don't have one but was thinking I might need one for the future. I have an infrared temp gun, I assume thats what I will need to check the temps. Can you explain what your looking for when checking temperatures over the tread patten and what adjustments should be made depending on where the hot spots are?

Is this something that I should be doing at all events? To be honest I always thought the guys doing this looked a little silly and taking it to be what seemed a little too serious. But I sort of felt that way because many of the guys I observed doing it at my events sucked at driving... My times were consistently better and I was not concerned about the little details yet... Just out there to have fun and do as well as I could.

 

You can check with the organizers of the EVO school site to see if they will have a compressor with air available, usually they will, if not then you can bring your own air.

Air pressure is key to making best use of your tires. Tires do a lot of work, allowing you to turn, accelerate, and brake better if you are using the full contact of the tread patch.

If tire pressure is too high the tire temperature in the middle will be higher than the edges. If tire pressure is too low the tire temperature on both edges will be higher than the middle. If the temperature is nearly the same for the middle and one of the edges then that is what you are looking for. The other edges of tires in the fronts will get hot faster when you have more turns. The inner edges of tires tend to get hotter when you have excessive negative camber and you don't have many turns to heat up the outer edges.

Tire temperature is best checked with a probe style pyrometer rather than the infrared type because you want the temperature of the tread down inside a little not at the surface which heats up quickly then cools down. Don't wait long after driving when checking temperatures as they cool off immediately. Just get to a safe area where you can get out and check the temperatures, fronts first and make a note of what you have.

Often right or left front tire temperatures will be hotter than the rest. If you have more high speed or tight left turns the outer right front tire will be hotter, less so for the right rear tire.

Checking and changing tire pressures allows you to easily and quickly change understeer or oversteer tendencies of the car for a given style of driving. Tire pressures can be slightly higher in front to reduce understeer.

Tires function their best when operating at their optimal temperature. Too cold or too hot does not allow for maximum grip. Adequate air pressure helps you more evenly use your full tire tread and heat up the tire uniformly. You also wear the tire more evenly.

For street tires you don't have to worry about exact optimal tire temperatures like you may for R compound tires but it's good to heat up your tires slowly. It is possible that with very hard driving on cold street tires that are fairly new you could overheat the surface of the tread blocks and cause them to shear off in chunks. That can happen on the track with lapping. I don't think you will be driving enough at Evo school for that to happen but it's good to warm up in the first few runs.